Wireless Local Area Networks (WLANs) are being contemplated or are known. Such WLANs are typically supported by WLAN servers, which may alternatively be referred to as private branch exchanges (PBXs) or enterprise servers. The PBX normally provides a control and switching function for the WLAN and communication units operating therein or users thereof. The WLAN can be an attractive and inexpensive alternative for typical voice services such as telephony or dispatch services and may provide additional amenities such as high-speed wireless Internet and Intranet access as well as other real-time applications that may be more specific to a given enterprise.
Wireless wide area networks (wireless WANs or WANs) such as conventional cellular telephone systems are also known. Such networks provide the advantage of wide area coverage but may not be economically attractive for routine access to wideband or high speed data capabilities, such as are required for certain Internet or Intranet applications. Nevertheless a communication unit that is operating on a WLAN may move beyond the effective service area for the WLAN and thus need support or services from a WAN. In situations, sometimes referred to as loosely coupled systems, where the WAN is essentially not aware of the WLAN or communication unit operating thereon this can present problems, particularly for ongoing communication and handoffs or handovers thereof.
Therefore, a need exists for methods and apparatus to support handovers or handoffs between a first and a second communication network